The book creates a new language, what the authors call a pattern language derived from timeless entities called patterns. As they write on page xxxv of the introduction, “All 253 patterns together form a language.” Patterns describe a problem and then offer a solution. In doing so the authors intend to give ordinary people, not only professionals, a way to work with their neighbors to improve a town or neighborhood, design a house for themselves or work with colleagues to design an office, workshop or public building such as a school. (Wikipedia)